Abstract: A method for synchronizing and connecting a first sub power system with a second sub power system with an intelligent electronic device (IED) by use of at least one switching device between the first sub power system and the second sub power system in an electrical power system is provided. The IED monitors power supply parameters such as voltage magnitude, phase and other derived parameters such as voltage and phase differences in the first sub power system and the second sub power system to identify at least one instance for fast bus transfer where the two sub systems have acceptable differences in magnitude and phase. The IED performs phase shifting and voltage magnitude correction in anticipation for synchronizing power supplies on connection at the identified instance.

Abstract: A method for synchronizing and connecting a first sub power system with a second sub power system with an intelligent electronic device (IED) by use of at least one switching device between the first sub power system and the second sub power system in an electrical power system is provided. The TED monitors power supply parameters such as voltage magnitude, phase and other derived parameters such as voltage and phase differences in the first sub power system and the second sub power system to identify at least one instance for fast bus transfer where the two sub systems have acceptable differences in magnitude and phase. The TED performs phase shifting and voltage magnitude correction in anticipation for synchronizing power supplies on connection at the identified instance.

Abstract: The present invention is directed to a method and a system for fault detection analysis in a power device which is operatively associated with a differential protection unit. The power device has one input side and one output side through which an input current and an output current flows into and out from it, respectively. Signals representative of the input and output currents are processed in order to verify if an occurring fault is external to the power device. Under a condition of an external fault, the differential protection unit is disabled for a determined interval of time.

Abstract: The present invention is directed to a method and a system for fault detection analysis in a power device which is operatively associated with a differential protection unit. The power device has one input side and one output side through which an input current and an output current flows into and out from it, respectively. Signals representative of the input and output currents are processed in order to verify if an occurring fault is external to the power device. Under a condition of an external fault, the differential protection unit is disabled for a determined interval of time.

Abstract: A protective relay for an electrical power distribution system and a method. The protective relay includes first and second current transformers arranged to sense a respective current flowing into a power line, and a voltage sensing device arranged to sense the voltage of the power line. The protective relay further includes a first and a second device for determining the direction of a fault within the system based on a current signal from the first and second current transformers and a voltage signal from the voltage sensing means. The protective relay further includes a third device for determining the fault direction based on a sum of the current signals from the first and second current transformers and a voltage signal from said voltage sensing means. A controller determines whether a fault is internal or external based on the fault directions determined by the first, second and third devices.

Abstract: A protective relay for an electrical power distribution system and a method. The protective relay includes first and second current transformers arranged to sense a respective current flowing into a power line, and a voltage sensing device arranged to sense the voltage of the power line. The protective relay further includes a first and a second device for determining the direction of a fault within the system based on a current signal from the first and second current transformers and a voltage signal from the voltage sensing means. The protective relay further includes a third device for determining the fault direction based on a sum of the current signals from the first and second current transformers and a voltage signal from said voltage sensing means. A controller determines whether a fault is internal or external based on the fault directions determined by the first, second and third devices.